Apparatus for investigating earth formations



4 Sheets-Sheet 1 A. BLANCHARD APPARATUS FOR INVESTIGATING- EARTHFORMATIONS Sept. 8, 1959 Filed Sept. 23, 1955 l ylwmlmmll INVENTOR.ANDRE BLANCHARD. BY M4K/.r Aww HIS ATTORNEYA Sept. 8, 1959 A. BLANCHARDl APPARATUS FOR INVESTIGATING EARTH FORMATIONS 4 Sheets-Sheet 2 FiledSept. 25, 1955 INVENTOR.

BY @2M M. A

Y Anc/fie 5/0/7 c/Mr/" *N kN NN ATTORNEY Sept. 8, 1959 A. BLANCHARDAPPARATUS FOR INVESTIGATTNG EARTH FORMATIONS 4 Sheets-Sheet 5 Filed'sept. 25, 1955 FIG.3

INVENTOR.

l ANDRE BLANCHARD.

www4# HIS ATTORNEY.

Sept. 8, 1959 A. BLANCHARD 2,903,070

APPARATUS FOR TNVESTTGATTNG EARTH FORMATIONS Filed sept. 23, 1955 l 4vsheets-shew 4 FIC-3.4

INVENTOR.

ANDRE BLANCHARD.

BY y

HIS ATTORNEY.

United States 2,963,670 Patented Sept. 8, 1959 hee APPARATUS FonINvEsrioATlNG EARTH ronMArIoNs Andre Blanchard, Houston, Tex., assigner,'by mesue assignments, to Schlumberger Well Surveying Corporation,Houston, Tex., a corporation of Texas Application September 23, 1955,Serial No. 536,190 Claims. (Cl. `16h- 100) This invention relates toapparatus for investigating earth formations, and more particularly,pertains to a new and improved projectile for use in an earthy formationiiuid sampler.

One type of `tluid sampler proposed heretofore come prises a hollowprojectile disposed within a gun block adapted to be lowered through aborehole to a position adjacent a formationof interest. At the desiredlevel, a propellant contained by the gun block is detonated thereby tofire the projectile into the formation. The projectile is connected to areservoir by la flexible tube and has a normally closed front aperturewhich is opened so that formation fluid may pass through the projectileand the iiexible tube into the reservoir where lit is retained by meansof a check valve. The apparatus may `then be raised to the surface wherethe sample can be recovered from the reservoir.

Experience has shown that when a solid object penetrates a formation,its lithology changes; usually the result is in the nature of acompaction of the formation. For example, if an object is forced into asand body which does not change in volume, the voids in the sand bodyare decreased by the volume of the object. Such va decrease ordinarilytakes `place in the innnediate vicinity of the object.

As these voids are decreased, `the `sand grains are pushed yinto oneanother in such a manner ,that they `are crushed into an extremely fnematerial, and the penne ability of the sand immediately adjacent tothensurface of the object approaches Zero. Thus it may be difficult, ifnot impossible, to obtain ,a sample of fluid from `many formations.

It is an object ,of the present invention, therefore, to provide a newand yimproved projectile for an earth formation iiuid sampler whichovercomes the undesirable effects of compaction of formation materialinto which the projectile i's driven.

Another object ofthe present inventionis to provide a new and improvedprojectile for an earth formation lluid sampler for obtaining samples offormation iiuids with greater reliability than heretofore possible. Inaccordance with the present invention, a projectile for anearthformation fluid sampler comprises a hollow body adapted to beimpelled toward a selected earth formation and having ajfrangiblewallportion. An explosive material is lpositioned within ythe hollowbodychamber and means are provided for detonating the explosive material torupture the frangible wall portion andto penetrate formation material.Thus, a `iiuid communication path `is established between the selectedearth formation ,and a tube which may be l'uidly connected tothe hollowbody. Y

The novel features of the present invention are set forth withparticularity in the appended claims. The present invention, both as toits organization and manner of operation, together with further objectsand advantage'sthereof, may best be understgod by` referenceV to thefollowing description taken in connection with the accompanying drawingsin which:

Fig. 1 is a view in longitudinal cross section of an earth 'formationiluid sampler incorporating a projectile embodying the presentinvention, the liuid sampler being represented schematically and in onecondition of operation;

Pigs. lA-lF are cross-sectional views of the apparatus illustrated inFig. 1 taken along lines lA-lF, respectively, and drawn to au enlargedscale;

Fig'. 2 is a view similar to the one shown in Fig. 1, but drawn to asmaller scale and illustrating the fluid sampler in another condition ofoperation;

Figs. 3 and l4 represent a modification which may be made to theapparatus of Figs. 1` and 2 according to auother embodiment of theinvention; and

'Fig 3A is an enlarged view in longitudinal cross section of a portionof the projectile shown in Figs. 3 and 4.

In Fig. 1 of the drawings there is illustrated diagrammatically aportion of a sampler unit =10 including a gun blockhll and asample-receiving chamber 12. Sampler unit 1t) (excluding the projectileof the present invention) may be constructed in the manner described inthe copending application of R. Q. Fields, filed September 23, 1955,bearing the Serial No. 536,204 and assigned to the same assignee as thepresent invention. Although but a single unit is illustrated, anydesired number of units may be employed, and the entire assembly issuspended in a borehole 13 by a cable (not shown) in the customarymanner.

Borehole 13 ytraverses earth `formations such as the ones designated 14,15, and 16 and may be filled with a drilling liuid 9. It is assumed thatformation `15 is the selected one from which a uid sample is to be takenand the sampler vunit 10 is positioned in the borehole with its gunblock 11 opposite this formation.

Disposed within a cylindrical, transverse bore 17 of gun block 11 is acylindrical, hollow projectile 18 embodying the present invention. Theprojectile 18 includesa Irear Vend portion 19 slightly smallerthan bore17 and an O ring 20 seated in an annular groove 2-1 provides a fluidseal )between end portion 19 aud the wall of bore 17. A taperedsectionZZ extends between rear `portion 19 and a forward portion 23 of asmaller di'- ameter terminated by a conical formation-penetrating nose24. This type of construction is disclosed in the copenfding applicationof Maurice Mennecier, filed Septe'mber 23, 1955, bearing the Serial No.536,251 and assigned to the same assignee as'the present invention. Thewall of nose 24 is strong enough to resist the impact of the projectileon the formation, but is frangible at a central section 24 in responseto the explosive force produced by the detonation of an explosive charge25 disposed in a forward chamber 26. The required physicalcharacteristics for projectile 18 may be provided by theuse ofanappropriate material, such as steel, selected in a known manner. Theforward end of chamber 26 is connected by a frusto-conical transitionsection 26 to a smaller cylindrical depression 26" that terminateswithin wall section 24.

The charge Z5 is comprised of ahollow cylindrical container 27 lled withan explosive material 28, such as cyclonite. The forward end of theexplosive material is hollow and is fitted with a suitable conicallyshaped Iliner 29. Thus, charge 25 will be recognized as a conventionalform of shaped explosive charge which upon detonation produces aperforating jet extending forwardly along a jet axis aligned along theprincipal longitudinal axis for the projectile 1S, denotedjby brokenline 3u. Cylindrical container 27 has a diameter smaller than thediameter of chamber 26 to provide a void or cushion lspaceforv theexpansion of gases resulting from the detonation of charge 25.

lf desired, the rear end of explosive material 28 may comprise a leadazide booster adjacent a disk-like flange 31 that effectively closes therear end of retainer 27. Flange 31 is an integral part of anotherretainer having a cylindrical body portion 32 somewhat smaller thanretainer 27. Body portion 32 extends along axis 30 from thefirst-mentioned chamber 26 into a second chamber 33.

Flange 31 and the body portion 32 have an axial opening 34 lled with adelay explosive 35, such as black powder, as may also be seen in Fig.lA. Cylindrical body portion 32 of the retainer has a diameter smallerthan the diameters of chambers 26 or 33 to provide an expansion spacefor gases resulting from the detonation of explosive 35. The interior ofbody portion 32 communicates with the expansion space via a plurality ofopenings 32a. The rearmost end of the delay explosive is in contact witha primer cap 36 received by an enlarged section 37 of the body portion32, also shown in Fig. 1B. Section 37 has a diameter essentially equalto the diameter of chamber 33 and is provided with a plurality of uidpassages 38 extending parallel to axis 3).

Extending through chamber 33 in close fitting relation with the wallthereof is a metal sleeve 39 having its foremost end engaging section 37and a rear end portion threaded to the Wall of chamber 33. Disposed atequally spaced intervals about its inner periphery are a plurality ofridges 4t) which are parallel to axis 30. These ridges form a guide(Fig. 1C) for a tiring pin 41 having a forward projection 42 alignedwith primer cap 36, and the space between the ridges provides a bypassaround pin 41. As best seen in Fig. 1C, openings 40 through the solidrear section of element 39 are aligned with the spaces between theridges 40. The firing pin 41 has a lateral opening 43 which receives oneend of a shear pin 44 that extends laterally into an opening 4S insleeve 39. Thus, the tiring pin is normally held in a quiescent positionas shown; however, in response to a force at least equal to apredetermined inertia force developed by the deceleration of projectile18 as it enters the selected earth formation, shear pin 44 issheared andthe ring pin moves to an active position in engagement with primer cap36, as will be more apparent from the discussion to follow.

At the rearmost end of chamber 33 there is positioned a fluid lter 46comprised of three disk-like screens 47 (Fig. 1F) separated by spacers48 having appropriate fluid passages. These passages are in the form ofinner and outer groups 48a and 48h of openings terminating in respectiveannular grooves 48C and 48d in a face of the spacer, as may be best seenin Fig. 1E. A closure 49 fluidly seals the rear end of projectile 18 andhas an axial opening t) for receiving one end of a ilexible tube 51 towhich it is mechanically connected in an appropriate manner. Forexample, the tube may be silver soldered to the wall of opening 50, witha mass of bonding material 52 being provided on the tube. Thus, the tubeis uidly sealed to the wall of opening 50, while a strong mechanicalconnection for forward movement with closure 49 is afforded. Tube 51 isin fluid communication with chamber 33 and is wound into a plurality ofhelical turns disposed at the rear end of gun bore 17. The remainingextremity of tube 51 is iluidly connected to a conduit 53 that extendsto sample-receiving chamber 12.

A propellant such as an explosive material 54 is disposed at the rearend of gun bore 17 and within the convolutions of tube 51. An electricaligniter 55 extends through a transverse opening 56 in gun block 11 intobore 17 where it is in contact with explosive 54.

To condition the fluid sampler for operation, chamber 12 may beevacuated or filled with a uid at a pressure lower than the pressure offormation fluids. For example, chamber 12 may contain air at atmosphericpressure before it is installed and the apparatus is lowered intoborehole 13. When gun block 11 is opposite formation 15, an appropriateelectrical circuit is completed between a Source of electrical energy(not shown) and igniter 55 thereby to detonate explosive 54 andprojectile 18 is impelled out of gun bore 17 into the formation. Aspointed out earlier, formation-penetrating nose 24 is strong enough towithstand the impact as projectile 18 passes into formation 15. Ofcourse, tube 51 uncoils and thus extends from the gun bore 17 as shownin Fig. 2. When projectile 18 strikes the formation, the resultinginertia force on firing pin 41 breaks shear pin 44 and permits thefiring pin to move forward and strike primer cap 36 thereby to ignitedelay explosive 35. The length and composition of the delay explosiveare chosen so that there is sufficient time for projectile 1S to come torest in the formation before explosive 2S is detonated. Thus, after theprojectile is imbedded in formation 15, the perforating jet from shapedcharge 25 ruptures the frangible wall portion 24 of nose 24 and theperforating jet penetrates into the formation as illustrated by the coneshaped opening 57 in Fig. 2. The differential pressure between thecolumn of drilling mud 9 and the formation fluid helps to hold theprojectile in place during this portion of an operating cycle.

lt is apparent that a fluid communication path is completed betweenformation 15 and chamber 33 via openings 26, 26' and chamber 26.Accordingly, formation iluid may How through chambers 26 and 33, filter46, tube 51, conduit 53 and into sample-receiving chamber 12.

Even though compaction may occur in formation material immediatelyadjacent the forward end of projectile 18, the perforating jet producesthe opening 57 in the formation which extends through the compacted zoneand iluid may ow readily. Thus, by using a projectile embodying thepresent invention, samples of formation fluid may be consistently andreliably taken.

After chamber 12 is lled, unit 10 is drawn upwardly to close a valve(not shown) in the fluid path to the chamber 12 and to break tube 51.Thereafter, the unit may be raised to the surface of the earth where thesample is removed.

In the modication illustrated in Fig. 3, elements which correspond tolike elements in Fig. 1 are identified by the same reference numerals.As shown in Fig. 3, an elongated cylindrical projectile 18 is receivedwith the cylindrical, transverse bore 17 of the gun block 11. Instead ofa shaped charge explosive as shown in Figs. 1 and 2, an explosive charge60 of generally cylindrical coniiguration is disposed in a forwardchamber 26a (Fig. 3A) of projectile 18. An annular wall portion 61 ofthe projectile in the vicinity of explosive charge 60 and nose 62 areconstructed of a frangible material. Disposed rearwardly of theexplosive charge 60 are a delay explosive 35, a tiring pin 41 in therrward chamber 33, a lter unit 46 and a lluidly connected iiexible tube51.

The delay explosive 35 is received by a cylindrical container 27disposed in the forward chamber 26a and has at its rear end a disc-likeflange 31 that effectively closes off the rearward end of retainer 27.Flange 31' is an integra-l part of another retainer having a cylindricalbody portion 32' somewhat smaller than retainer 27. Body portion 32extends along the central axis of the projectile from thefirst-mentioned chamber 26a into the rearward chamber 33.

Flange 31 and body portion 32 have an axial opening 34 which contains aportion of the delay explosive 35. Cylindrical body portion 32 has aplurality of openings 32h therein and is smaller than the diameters ofchambers 26a or 33 to provide an expansion space for gases resultingfrom the detonation of explosive 35'. The rearmost end of the delayexplosive is in contact with a primer cap 36 received in an enlargedsection 37 of the body portion 32'. Section 37 has a diameter equal tothe diameter of chamber 33 and is provided with a plurality of{iuidpassages 3s' extendingp'arallei to the central axis of l the'projectile.

Extending through chamber 33 inv close' fitting relation with' the" wallthereof is a tubular rneta'l sleeve 39 having its foremost end engagingsection 37 and a rear portion threaded to the wall ofch'arnbe'r 33.Sl'idably disposed in sleeve 39' is a cylindrical firing pin 4I' havingaforward projection 42 aligned with primer cap 36. Pin 41 has" axial'openings 4i extending therethrough to permit llluid flow through thepin, and a transverse opening 45 which receives a shear pin 44 that.extends laterally into an opening 45 in sleeve 39. Thus, the firing pinis normally heldin a quiescent position as shown; however, in response'to a force at' least equal to a predetermined ifieitia force developedby the deceleration of projectile 18 as it enters the selected eartlrformation, shear pin dfi ssheared and the firing pin movesto anA activeposition in' engagement with the primer cap 36'.

Aty thev rear-most end of chamber 33 there is positioned a uid filter docomposed of a cylindrical body 46 threaded to the sleeve 39 and havinglateral openings in communication with a central opening 50'. A screenSti of suitable mesh surrounds the body 46 to filter fluid flowtherethrough. `Onel end of a flexible tube 51 is receivedin opening Stiand is mechanically connected in a suitable manner'. In operation, asmay be evident in Fig. 4, when the explosive 60 is detonated after theprojeotile 18 comes to rest in the selected formation, explosive forcesrupture portions 61' and 62 and the entire corneal foreward end of theprojectile is blown out. The explosive force also produces an opening 63in the formation material of generally spherical, although irregularconfiguration. While the type of explosion produced by the cylindricalcharge may tend to compact the formation in the immediate vicinity ofprojectile 18', it also produces cracks which effectively increase theformation permeability. Accordingly, a fluid communication path isestablis-hed between the formation and the tube Si through theprojectile i8v in essentially the same manner described inconnectionwith the embodiment of Figs. 1 and 2.

While particular embodiments of the present invention have been shownand described, it is apparent that changes and modifications may be madewithout departing7 from this invention in its broader aspects, andtherefore, the aim in the appended claims is to cover all such changesand modifications as fall within the true spirit and scope of thisinvention.

I claim:

1. In an earth formation Jfluid sampler having a fluidconveying tube, aprojectile comprising: a hollow body having an opening therein adaptedto be liuidly connected to the fluid-conveying tube, said body beingadapted to be impelled toward a selected earth formation, and having aformation-penetrating frangible wall portion; an explosive materialpositioned within said hollow body; and means in said body operativesubsequent to penetration of said wall portion in a formation fordetonating said explosive material to rupture said frangible wallportion thereby to permit fluid flow between the selected earthformation and the fluid-conveying tube.

2. In an earth formation fluid sampler, a projectile comprising: a bodyadapted to be impelled toward a selected earth formation and including aformation-penetrating end portion having a frangible wall, said bodyhaving a first chamber disposed adjacent said frangib'le wall, and asecond, samplereceiving chamber fluidly communicable with said firstchamber; a shaped explosive charge positioned in said first chamber andhaving a forward end from which a perforating jet emanates upondetonation of said charge, said forward end facing said frangible wall;and means in said body `operative subsequent to penetration of said bodyin a formation for detonating said explosive charge to rupture saidfrangible wall portion thereby to permit fluid flow between thc selectedearth formation and said second chamber.

3. In an earth formation uuid. sampler, a projectile comprising: a bodyadapted to be impelled toward a selected earth formation and including aformation-pene trating forward end having a frarigible wall and arearward end having an opening therein arranged to be mechanicallyconnected to a sample-conveying tube, said body having a chamberextending along a principal axis intersecting said forward and saidrearward ends and including a first section adjacent said frangible wallportion and a second, sample-receivihg' section uidly communicable withthe sample-conveying tube; a shaped explosive charge having -a forwardend from which a per# forating jet emanates along a jet axis upondetonatiori of said charge, said shaped explosive charge beingpositioned in said first chamber with said jet axis sub'- stantiallyaligned with said principal axis and with said forward end facing saidfrangible wall; means in said body operative subsequent to penetrationof said body in a formation for detonating' said explosive charge torupture said frangible wall thereby to permit fluid flow between theselected earth formation and said second section of said chamber. y Y

4. In an earth formation fluid sampler, a projectile comprising: a bodyadapted to be impelled toward a selected earth formation arid includinga hollow front section defining an essentially cylindrical first chamberhaving an annular frangible wall portion, and a* hollow rear sectiondefining `a second, sample-receiving charn-` ber fluidly communicablewith said `first chamber and having an opening therein arranged to becoupled to a sampleeconveyingl tube; an explosive material positioned insaid first chamber to apply radially directed' rupturing forces to saidfrangible wall portion when detonated thereby to permit fluid ow betweenthe selectedr earth formation and said second' chamber; and means insaid body operative subsequent to penetration of said body in theformationvfo'r detonatingsaid explosive material'.

5. In an earth formationfiuid sampler, a projectile comprising: a bodyadapted yto 'be impelled toward a selected earth formation and having a'forward extremity adapted to initially penetrate an earth formation,said forward extremity including a formation-penetrating frangible wallportion, said body further having a first chamber disposed adjacent saidfrangible wall portion and a second, sample-receiving chamber in arearward portion of said body flui'dly communicable with said firstchamber; an explosive material positioned in said first chamber adjacentto said frangible wall portion; and means in said body operativesubsequent to penetration of said `body in a formation for detonatingsaid explosive material to rupture said frangible wall portion therebyto permit huid flow between the selected earth formation and said secondchamber.

6. In an earth formation fluid sampler, a projectile comprising: a bodyadapted to be impelled toward a selected earth formation and having aforward extremity adapted to initially penetrate an earth formation,said forward extremity including a formation-penetrating frangible wallportion, said body further having a first chamber disposed adjacent saidfrangible wall portion, and a second sample-receiving chamber in arearward portion of said body fluidly communicable with said firstchamber; an explosive material positioned in said first chamber adjacentto said frangible wall portion; and inertiaresponsive means in said bodyoperative subsequent to the penetration of said body in a formation fordetonating said explosive material to rupture said frangible wallportion thereby to permit fluid flow between the selected earthformation and said second chamber.

7. In an earth formation fluid sampler, a projectile comprising: a lbodyadapted to be impelled toward a selected earth formation and having aforward extremity adapted to initially penetrate an earth formation,said forward extremity including a formation-penetrating '7 frangiblewall portion, said body further having a rst chamber disposed adjacentsaid frangible wall portion and a second sample-receiving chamber in arearward portion of said body uidly communicable with said firstchamber; an explosive material positioned in said first chamber adjacentto said frangible wall portion; and a detonating system in said bodyoperative subsequent to penetration of said body in a formation fordetonating said explosive material torrupture said frangible wallportion thereby to permit fluid flow between the selected earthformation and said second chamber, said detonating system including adelay explosive adjacent said explosive material, a primer cap adjacentsaid delay explosive and la tiring pin movable from a quiescent positionto an active position in engagement with said primer cap in response toa force at least equal to a predetermined decelerative force developedupon entry of said body into the selected earth formation.

8. In an earth formation fluid sampler, a projectile comprising: a bodyadapted to be imbedded in a selected earth formation and having aforward extremity adapted to initially penetrate an earth formation,said forward extremity including a frangible wall portion, said bodyfurther having a rst chamber disposed adjacent said frangible Wallportion and a second sample-receiving chamber in a rearward portion ofsaid body uidly communicable with said rst chamber adjacent to saidfrangible wall portion; an explosive material positioned in said firstchamber for generating an explosive force greater than required torupture said frangible wall portion; and means in said body operativesubsequent to the imbedding of said body in the selected earth formationfor detonating said explosive material to rupture said frangible wallportion and to penetrate the formation thereby to permit fluid flowbetween the formation and said second chamber.

9. In an earth formation uid sampler, a projectile comprising: a bodyadapted to be impelled toward a selected earth formation and having aforward extermity adapted to initially penetrate an earth formation,said forward extremity including a wall portion strong enough to resistforces developed by entry of said body into the formation, but frangiblein response to a given force, said body further having a rst chamberdisposed adjacent said wall portion and a second sample-receivingchamber in a rearward portion of said body fluidly communicable withsaid chamber adjacent to said frangible wall portion; an explosivematerial positioned in said rst chamber for developing an explosiveforce greater than said given force; and means in said body fordetonating said explosive material to rupture said frangible wallportion thereby to permit fluid ow between the selected earth formationand said second chamber.

10. In an earth formation fluid sampler, a projectile comprising: ahollow, generally cylindrical body including a closedformation-penetrating forward extremity adapted to initially penetratean earth formation, said body being adapted to be impelled toward aselected earth formation, and said body having a frangible wall in atleast a portion thereof including said formationpenetrating end and anannular zone contiguous to said end, said body further having a rstchamber disposed at least in part adjacent said frangible wall, andhaving a second sample-receiving chamber in a rearward portion of saidbody iluidly communicable with said first chamber; an explosive materialpositioned in said rst chamber adjacent to said frangible wall portion;and means in said body operative subsequent to penetration of said bodyin the formation for detonating said explosive material to rupture saidfrangible wall portion thereby to permit fluid flow between the selectedearth formation and said second chamber.

References Cited in the file of this patent UNITED STATES PATENTS2,286,673 Douglas June 16, 1942 2,408,419 Foster Oct. 1, 1946 2,545,306Pollard Mar. 13, 1951 2,582,719 Ramsey Jan. 15, 1952 2,679,380 SweetmanMay 25, 1954

1. IN AN EARTH FORMATION FLUID SAMPLER HAVING A FLUIDCONVEYING TUBE, APROJECTILE COMPRISING: A HOLLOW BODY HAVING AN OPENING THEREIN ADAPTEDTO BE FLUIDLY CONNECTED TO THE FLUID-CONVEYING TUBE, SAID BODY BEINGADAPTED TO BE IMPELLED TOWARD A SELECTED EARTH FORMATION, AND HAVING AFORMATION-PENETRATING FRANGIBLE WALL PORTION; AN EXPLOSIVE MATERIALPOSITIONED WITHIN SAID HOLLOW BODY; AND MEANS IN SAID BODY OPERATIVESUBSEQUENT TO PENETRATION OF SAID WALL PORTION IN A FORMATION FORDETONATING SAID EXPLOSIVE MATERIAL TO RUPTURE SAID FRANGIBLE WALLPORTION THEREBY TO PERMIT FLUID FLOW BETWEEN THE SELECTED EARTHFORMATION AND THE FLUID-CONVEYING TUBE.